Light bars for mounting on emergency vehicles such as police cars, ambulances, fire trucks, etc. for providing warning signals come in a variety of sizes, shapes, configurations, and functions. Some light bars have a plurality of lights of different types enclosed in one housing (which may have several sections). An important advantage of such light bars over simple domeshaped warning lights is their versatility. Many different types of lights, such as stationary, strobe, oscillating, and rotating lights, can be packaged in the housing of a light bar to provide a variety of light options having different colors, intensity variations, and timing sequences for different purposes. For example, a light bar may be equipped with transient lights for warning signals, an array of stationary lights sequentially flashed to provide traffic management signals, and flood lights for illumination purposes. It is also common to include a speaker in a light bar for providing audio warning signals.
The lights enclosed in a light bar are typically customized according to the specific combinations desired by customers. Due to the different budgets, applications, and preferences of the customers, the specific combination of lights in a given light bar model may differ significantly from order to order. Thus, the light components in a light bar are typically mounted in an ad hoc fashion one by one into the housing. Such an assembling process can be rather labor intensive and slow, thereby increasing the cost of the light bar.
Moreover, it is difficult to design the layout of a given light bar model to be sufficiently universal to accommodate all different combinations desired by customers. In existing light bars with a plurality of lights enclosed in a housing, the light fixtures are typically fastened by screws onto a metal structural support member, and the number of lights and the possible combinations of lights are significantly restricted by the length and structure of the metal structural member. In some cases, significant modifications of the metal structural member or the shells of the housing would be required in order to accommodate certain light combinations. Such modifications, however, can be prohibitively expensive.
A related common problem with existing light bars is that the access to individual components in a light bar may become blocked as more components are packed in the housing of the light bar, thereby compromising the serviceability of the light bar. This problem is especially prominent in certain existing two-level light bars, in which the lights mounted on the upper level and the dividers separating the two levels tend to block direct access to the lights on the lower level. Thus, even simple service jobs, such as replacing a light bulb or removing a color filter, can be rather time consuming and inconvenient.
Another unsatisfactory aspect of existing light bars is the way speakers are incorporated in the light bars. Light bars with speakers commonly have multiple sections, and the section containing the speaker is separated from other sections containing lights. The speaker section is typically covered by a formed sheet-metal cover which has perforations or slots to allow sound to be transmitted to the exterior. Light devices, which can be damaged by water, dust, etc., cannot be used in the speaker section. This not only results in significant waste of valuable interior space but also compromises the flexibility in combining lights into different patterns.